Motor-operated rotary hammer



R. E. COVERT.

MOTOR OPERATED ROTARY HAMMER. APPLICATIQM FILED NOV. 23, 1.917. RENEWED05c. 30, 1919.

1,341,54 Patented May 25,1920.

NITED STATES RALPH E. COVERT, 015 DETROIT, MICHIGAN.

MOTOR-OPERATED ROTARY HAMMER.

Specification of Letters Patent.

Patented May 25, 1920.

Application filed November 23, 1917, Serial No. 203,647. RenewedDecember 30, 1919. Serial No. 348,376.

To all whom it may concern:

Be it known that I, RALPH E. Covnn'r, a citizen of the United States,residing at Detroit, in the county of lVayne and State of Michigan, haveinvented certain new and useful Improvements in Motor- Operated RotaryHammers; and I do hereby declare the following to be a full, clear, andeXact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same.

The invention relates to a motor operated rotary hammer.

The object of the present invention is to provide a simple, practicaland eflicient motor operated rotary hammer of strong, durable andinexpensive construction designed for riveting and various otherpurposes and capable of being readily operated by an electric motor.

Vith these and other objects in view, the invention consists in theconstruction and novel combination of'parts hereinafter fully described,illustrated in the accompanying drawing and pointed out in the claimshereto appended; it being understood that various changes in the form,proportion, size and minor details of construction, within the scope ofthe claims, may be resorted to without departing from the spirit orsacrificing any of the advantages of the invention.

In the drawing:

Figure 1 is a side elevation of a motor operated rotary hammerconstructed in accordance with this invention.

Fig. 2 is a sectional view through the easing of the rotary hammer.

Fig. 3 is a similar view on the line 3-3 of Fig. 2.

Like numerals of reference designate corresponding parts in the severalfigures of the drawing.

in the accompanying drawing, in which is illustrated the preferredembodiment of the invention, the motor operated rotary hammer comprisesin its construction a casing l composed of sections 2 secured togetherby bolts 3 or other suitable fastening devices and having a centralbearing opening 4 for the reception of a driving shaft 4 of a rotarydriving member or hammer 5. The rotary driving member or hammer '5 iscentrally secured to the shaft 4* and it extends through a central space6 of the casing to a substantially annular passage 7 which forms a raceway. The annular passage is provided with circular inner wall 8 arrangedconcentric with the shaft and it has an outer wall consisting of aconcentric portion 9 and eccentric portion 10. The raceway receivesheads 11 of the rotary hammer or driving member which is adapted toactuate balls 12. The casing is provided at the eccentrically arrangedportion 10 of the passage with an opening 14 for the reception of arivet set or tool 13 having a head 15 which is adapted to engage therivet and which also is engaged by a shoulder 16 formed by anenlargement of the opening 14 and adapted to limit the inward movementof the rivet set or tool. The rivet set or tool is provided with aninclined or angularly disposed inner end 17 which projects inwardly intothe raceway into the path of the balls, as clearly illustrated in Fig. 2of the drawing, and the said inclined or angularly disposed face isadapted to eliminate rebound of the balls and the eccentrically arrangedportion of the outer wall provides siniicient space for the balls topass the rivet set and gain sufficient speed to enable them to pass infront of the rotary member or hammer. A ball is arranged at each side ofthe rotary hammer or driving member, which has each of its headscooperating with one of the balls. The balls are driven around theraceway and they strike the rivet set or tool and produce anintermittent driving of the same similar in effect to a pneumatichammer. The balls 12 are moved through the raceway 7 by being engaged bythe heads 11 of the hammer, the balls during this movement being inloose contact with the hammer head. When one of the balls engages theinner end of the tool 13. its movement is momentarily stopped, and thisball is then struck by the head 11 of the hammer a blow of great forceso as to impart a downward or outward impulse .to the tool, the ballthus acting to transmit the blow of the hammer head directly to the toolin much the same manner as if the tool were struck squarely upon itsinner end by a manually operated hammer. By having the ball entirelyfree from the hammer head, and only in loose contact therewith. a blowof much greater force is obtained than is possible in rotary hammers ofordinary construction in which the heads of the hammer itself aremovable radially, or substantially so, of the operating shaft so thatthese heads have merely a wiping effect upon the inner end of the toolso as to tend to force it outwardly by centrifugal force, but do notexert any positive hammering effect.

The shaft 4* is adapted to be actuated by an electric motor 18 which isconnected at 19 with the hammer casing, and while the motor is showndirectly connected with the shaft 4P any suitable gearing may of coursebe employed for increasing or diminishing the number of revolutions ofthe shaft. The hammer casing is provided with a handle 20 and is adaptedto be manipulated in the same manner as a pneumatic hammer. In theoperation of the device, the head of the rotary driving member or hammerstrikes a ball to drive the same around the raceway with Su cient speedto enable the balls to contact with and deliver a blow to the rivet setand pass'in front of the cooperating hammer head. The centrifugal forcewill cause the balls to hug the outer wall of the passage and the innerend of the rivet set projects into the path of the balls but is locatedbeyond the path of the actuating heads of the rotary hammer or drivingmember. Any suitable means may be employed for limiting the outwardmovement of the rivet set when desired.

What is claimed is:

1. A motor actuated rotary hammer including a casing having a raceway, ashaft journaled in the casing, a rotary hammer carried by the shaft anextending into the raceway, a ball free from the hammer open ai i th raway and g ged y S i hammer, and a tool member protecting into the pathof the ball.

'2. A motor operated rotary hammer in eluding a casing having asubstantially annular'raceway provided with an eccentri- 1 en arged p re ota y ha tending into the casing, a harnmer carried by h me yp 'h a eper t n h raceway, a ball free from the hammer and engaged therebyoperable in the raceway,

and a vibratory member located at the e'coentrically enlarged portion ofthe said raceway and projecting into the path of the ball and locatedbeyond the path of the hammer.

3. A motor operated rotary hammer including a casing provided with asubstan tially annular raceway having an enlarged eccentrically arrangedportion and provided thereat with a peripheral opening, a rotary shaftextending into the casing, a rotary hammer carried by the shaft andoperating in the raceway, a ball also operating in the raceway andactuated by the hammer, said ball being free from the hammer and avibratory member operating the peripheral opening and extending into thepath of the ball and located beyond the path of the hammer or drivingmember, said vibratory member being provided with an inclined orangularly disposed inner face adapted to eliminate rebound. i i

'4 A motor actuated rotary hammer including a casing having asubstantially annular raceway provided with an enlarged eccentricallyarranged portion, said casing being provided thereat with a peripheralopening, a rotary shaft extending into the casing, a hammer membercentrally connected to the shaft and provided at its ends with headsoperating within the raceway, balls also operatingwithin the raceway andlocated at opposite sides of the hammer, said ball being free fromthehammer, and a vibratory member extending into the path of the ballsand located beyond the path of the rotary hammer.

In testimony whereof I afiiX my signature in presence of two witnesses'DAVE LEVIN, L. l/V. Omi.

